// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "gin/wrappable.h"

#include "base/logging.h"
#include "gin/object_template_builder.h"
#include "gin/per_isolate_data.h"

namespace gin {

WrappableBase::WrappableBase()
{
}

WrappableBase::~WrappableBase()
{
    wrapper_.Reset();
}

ObjectTemplateBuilder WrappableBase::GetObjectTemplateBuilder(
    v8::Isolate* isolate)
{
    return ObjectTemplateBuilder(isolate);
}

void WrappableBase::FirstWeakCallback(
    const v8::WeakCallbackInfo<WrappableBase>& data)
{
    WrappableBase* wrappable = data.GetParameter();
    wrappable->wrapper_.Reset();
    data.SetSecondPassCallback(SecondWeakCallback);
}

void WrappableBase::SecondWeakCallback(
    const v8::WeakCallbackInfo<WrappableBase>& data)
{
    WrappableBase* wrappable = data.GetParameter();
    delete wrappable;
}

v8::Local<v8::Object> WrappableBase::GetWrapperImpl(v8::Isolate* isolate,
    WrapperInfo* info)
{
    if (!wrapper_.IsEmpty()) {
        return v8::Local<v8::Object>::New(isolate, wrapper_);
    }

    PerIsolateData* data = PerIsolateData::From(isolate);
    v8::Local<v8::ObjectTemplate> templ = data->GetObjectTemplate(info);
    if (templ.IsEmpty()) {
        templ = GetObjectTemplateBuilder(isolate).Build();
        CHECK(!templ.IsEmpty());
        data->SetObjectTemplate(info, templ);
    }
    CHECK_EQ(kNumberOfInternalFields, templ->InternalFieldCount());
    v8::Local<v8::Object> wrapper;
    // |wrapper| may be empty in some extreme cases, e.g., when
    // Object.prototype.constructor is overwritten.
    if (!templ->NewInstance(isolate->GetCurrentContext()).ToLocal(&wrapper)) {
        // The current wrappable object will be no longer managed by V8. Delete this
        // now.
        delete this;
        return wrapper;
    }
    wrapper->SetAlignedPointerInInternalField(kWrapperInfoIndex, info);
    wrapper->SetAlignedPointerInInternalField(kEncodedValueIndex, this);
    wrapper_.Reset(isolate, wrapper);
    wrapper_.SetWeak(this, FirstWeakCallback, v8::WeakCallbackType::kParameter);
    return wrapper;
}

namespace internal {

    void* FromV8Impl(v8::Isolate* isolate, v8::Local<v8::Value> val,
        WrapperInfo* wrapper_info)
    {
        if (!val->IsObject())
            return NULL;
        v8::Local<v8::Object> obj = v8::Local<v8::Object>::Cast(val);
        WrapperInfo* info = WrapperInfo::From(obj);

        // If this fails, the object is not managed by Gin. It is either a normal JS
        // object that's not wrapping any external C++ object, or it is wrapping some
        // C++ object, but that object isn't managed by Gin (maybe Blink).
        if (!info)
            return NULL;

        // If this fails, the object is managed by Gin, but it's not wrapping an
        // instance of the C++ class associated with wrapper_info.
        if (info != wrapper_info)
            return NULL;

        return obj->GetAlignedPointerFromInternalField(kEncodedValueIndex);
    }

} // namespace internal

} // namespace gin
